A synchronization type linear actuator that uses magnets as field systems is one type of linear actuators. This linear actuator includes a stator, which has a plurality of magnets arranged in a direction such that the polarities of the magnets are altered alternately, and a moving element, which has a plurality of coils arranged in the direction such that the coils face a row of the magnets of the stator (see Patent Literature Document 1). The coils are wound around salient poles of cores that face the row of the magnets of the stator. As an alternating current flows in the coils, the interaction between magnetic fluxes generated at the magnets and magnetic fluxes generated at the salient poles causes the moving element to move relative to the stator in the direction. The linear actuator that has the moving coils, such as the linear actuator disclosed in Patent Literature Document 1, is called a moving coil type linear actuator. A certain linear actuator has moving magnets, which move instead of the coils, and this linear actuator is called a moving magnet type linear actuator.